The purpose of this study is: 1) To establish a hospital-based case- control sample of 75 lung cancer cases and 75 controls. 2) Determine the frequency of genetic alterations in bronchial epithelium obtained by bronchoscopy from cases and controls and identify which changes show the strongest association with lung cancer. 3) Determine whether the three genetic alterations showing the strongest association with lung cancer are also present in exfoliated cells within sputum from controls whose bronchial cells exhibit these alterations.